/**
 * Copyright 2007 Jason Horman, Pete Aykroyd
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.functor.expression;

import java.beans.Statement;

/**
 * Reflectively calls "visit" method implementations on self. This allows for a
 * more dynamic dispatch than the normal visitor pattern. The most specific
 * visit method will be called before less specific implementations. This allows
 * subclasses to provide more specific implementations.
 */
public abstract class ExpressionVisitor {
	/** Start visiting the node reflectively. */
	public void start(Expression expression) {
		// create the reflective statement
		Statement statement = new Statement(this, "visit", new Object[] { expression });
		try {
			statement.execute();
		} catch (Exception e) {
			throw new RuntimeException(e);
		}
	}
}
